Natural waters and some aqueous waste streams contain appreciable quantities of dissolved silica which, during processing of the water, plate out as scales on the piping and the walls of the plant. It had not been possible to date to control silica scaling by the injection of additives, a technique which has been used successfully for other types of scaling compounds found in water and brines.
Scaling problems exist in the cooling systems of power plants where deposits of scale not only lower the heat transfer rate of vapor condensers but also impair the operability of the components and controls of the cooling systems. Scaling by silica and other scalants is a serious problem in the cooling towers of power plants.
In the desalination of sea water and brackish water, a deposit of scale interferes with the effective operation of the plant and may completely vitiate some of the plant components. This is particularly true in membrane processes, such as reverse osmosis and electrodialysis, where deposits of silica and other scales can clog the system and destroy the operability of the membranes.